For Wang, it wasn't enough to merely stop the crime on the scene.

"What's more important is to prove them guilty and hand them over to the police," she said.

Wang said she has been to the local police office so often that police recognize her and kindly remind her to be careful.

"It can be dangerous," said Wang when asked whether she was afraid of getting hurt. "Pickpockets once spat on me, slapped and cut my face with their umbrella when I attempted to chase them, but my trick is to suggest I am a plainclothes officer and there's backup around.

"Generally speaking, pickpockets have shifty eyes and they usually edge their way into the crowd. Rather than encourage eye contact, they only stare at your property such as your wallet and phone. Anyone from a couple, an old lady to a youngster could be their target."

Tang Wenlong, a local plainclothes police officer with a record of nabbing more than 1,500 pickpockets during his 21-year career, said Wang is on the right track of detecting pickpockets.

"Her spirit is splendid, but still, it isn't a wise decision for a young woman to take independent action, especially when she hasn't got any professional skills. Besides, she's unarmed while a pickpocket might have an accomplice around."

Wang explained that ever since a downtown police officer turned her down and told her "we couldn't put this case on record as we're in the middle of the high-crime-rate month" when she was handing a pickpocket to the local police office several years ago, she has been a member of the non-government organization Anti-pickpocket Alliance.

"Like a journalist, I use my camera to record faces of pickpockets and what they do, apart from stopping the crime," Wang said.Tang, the police officer, said he isn't on the side of the underground alliance as it might provoke violence.

"But it is true that we have our own system to follow. For example, we can't keep sick or pregnant pickpockets in prison," he said.

"So even if she finds the culprit, the police still can't detain that pickpocket. if she is pregnant."

Wang knows that well, but she insists that should not be an excuse to let such petty thieves go.

"We should always stop such crimes, shouldn't we?" she said.

Wang's micro blog on Sina Weibo is updated with many stories of her fighting pickpockets.

"I figured if we could rescue beggar children with weibo, why can't we post photos of pickpockets to keep the public alert?"